# $Mg_3N_2+6D_2O\rightarrow x$

$\begin{array}{1 1}(a)\;3Mg(OD)\\(b)\;2Mg(OD)_2\\(c)\;3Mg(OD)_2\\(d)\;3Mg(OD)\end{array}$

$Mg_3N_2+6D_2O\Rightarrow 3Mg(OD)_2 + 2ND_3$
$3Mg(OD)_2$
Hence (b) is the correct answer.
edited Nov 21, 2017